Lubricant



Patented Aug. 24, 1948 LUBRICANT John C. Zimmer, Union, and Gordon W. Duncan,

Westfieid, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application December 30, 1944, Serial No. 570,786

3 Claims.

The present invention relates to mineral lubricating oils, particularly those oils containing additives in the nature of detergents, rust preventives and extreme pressure agents. More particularly. the invention is concerned with compounded mineral lubricating oils which are not subject to or will not show additive separation in the presence of Water.

It is known that internal combustion engines, both of the Diesel type and of the spark ignition type, which are subject to long and continuous periods of use as, for example, in long-haul trucking service, construction tractor service, highspeed marine or railway service, certain types of aeronautical service, etc., require special lubricating oils, commonly designated as heavy duty oils, which are compounded especially for this type of service. Mineral lubricating oils which are not so expressly prepared deteriorate relatively rapidly in service, depositing sludge, carbonaceous materials, or varnish-like coatings on such surfaces as cylinder walls, piston skirts, piston ring grooves, etc. and creating an otherwise unclean condition within the engine. For the purpose of counteracting to as great an extent as possible the tendency of mineral lubricating oils to form these deposits, materials of a detergent nature are incorporated into mineral oils destined for hea y duty uses. Generally speaking, these additives are metallic derivatives of organic compounds, but regardless of their exact chemical configuration, they all exhibit the property of reducing or preventing the deposition of carbonaceous or gummy residues and varnish-like films resulting from the deterioration of the lubricating .oil. The more common of the detergent additives present in heavy duty oils in amounts ranging from 0.5% to 5% are such compounds as metal naphthenates,

metal phenates, metal phenol sulfides, and polysulfides, reaction products of metal phenol sulfides with phosphorus sulfides, metalcarboxylates, metal sulfonates, metal alcoholates, metal salts of esters of acids or thio acids of phosphorus, etc. where the metal ion is a polyvalent metal ion, such as calcium, barium, tin, aluminum, zinc, magnesium, strontium, lithium, nickel, etc. Certain non-metallic organic compounds are also employed on occasion.

Detergent additives used for improving mineral lubricating oils for heavy duty service are often somewhat hydrophilic and as a result they tend to form emulsions in the presence of water and to drop out of the oil solution, which action results in a heavy duty oil of impaired eiiectiveness. Normally, mineral lubricating oils used in internal combustion engines are not expected to come in contact with water. However, situations beyond the control of the oil refiner do arise where the prepared lubricating oil does come in contact with water and these occurrences present themselves with suflicient regularity that additive loss through contact with water becomes a serious problem. One instance where loss of additives through contact with water occurs is during shipment of the oil in large size drums or tank cars. Either through atmospheric condensation or leakage of rain water, or because, through oversight, it is left in the drum after cleaning, water is permitted to mix with the oil and precipitate out the detergent additive. Water may also come into contact with the oil in normal automotive operation, particularly during the winter, when low temperatures cause moisture to condense in the crankcase. Another instance where the deleterious action of water on compounded heavy duty oils has been noted is in connection with certain large Diesel installations Where, after installation or after the engine has been given a general overhauling, thewhole lubricating system including the oil reservoir is washed out with water and then flushed with some of the lubricant intended to be used for normal lubrication. After the flushing operation, the oil is centrifuged to dispose of the water and the oil is then put back into the oil reservoir. If the additive in the oil is hydrophilic in nature, this method of removing water from the oil also removes some of the detergent additive, and thus the oil returned to the system is not of the quality desired for such use. It is obvious from the foregoing that some means of retaining detergent additives in the oil even in the presence of water would be very beneficial.

The same phenomenon of additive removal resulting from water contamination and emulsification is encountered with certain soap-containing rust preventive agents and in other petroleum products containing metallo organic materials.

The principal object of the present invention resides in the provision of a compounded lubricant for use in the capacity set forth which, when accidentally or otherwise placed in contact or mixed with water, will not lose any substantial amount of the compounding agent. This and other objects to be attained by the use of the present skilled in the art upon reading the following description.

It has now been discovered that compounded oils and lubricants having dissolved therein appreciably hydrophilic detergent additives may be stabilized against emulsification and additive separation by the incorporation of certain oilsoluble organic hydrophilic compounds. The use of the term "oil-soluble organic hydrophilic compounds implies those organic materials which are miscible in oil and have, by virtue of certain substituent groups, an affinity for water. These materials are exemplified by aliphatic and cycloaliphatic alcohols having from 4-10.carbon atoms to the molecule, which may or may not invention will be apparent to those contain substituent ester, ether, ketone, or hydroxyl groups. Oil-soluble phenols, esters, ether esters, etc. exhibit lesser degrees of effectiveness. Specific examples of suitable materials are amyl alcohols, mixed amyl alcohols, methyl cyclohexanol, trimethyl cyclohexanol, 2-ethylhexyl alcohol, phenoxy ethanol, phenoxy isopropanol, tert. amyl phenoxy ethanol, and 2-ethylbutyl mono ether of ethylene glycol. Tertiary amyl phenol, iso-octyl phenol, diamyl oxylate and monomethyl ether of diethylene glycol acetate may also be employed with advantage.

The oils in such compounded oils and lubricants range in viscosity from 90-1800 S. U. S. at 100 F. with pour points usually from +25 F. to l F. and contain from 0.5% to of additives such as metal phenates, metal phenol sulfides, reaction products of metal phenol sulfides with phosphorus sulfides, metal carboxylates, metal sulfonates, metal naphthenates, metal alcoholates, metal salts of the esters of acids or thio acids of phosphorus, etc. or mixtures of the foregoing additives.

In general the metallo organic'compounds utilizable as detergent additives contain ions of polyvalent metals, specific examples being calcium, barium, aluminum, tin and zinc. The non-metallic detergent additives include materials such as the naturally occurring phosphatides. The usual method of blending compounded oils is to use an oil concentrate of the additive which is dissolved in the mineral oil in the required amount to give the desired product, which,solution may be hastened by means of agitation and heat. These detergent additives are frequently made in situ in oil solutions so that after removal of the by-products of the reaction, an oil concentrate of the desired additive is obtained directly and this is then used later to make the finished oil by blending it with the proper amount of the base stock.

A specific and preferred detergent additive is a mixture of an alkaline earth metal sulfonate and an alkaline earth metal aikylated phenol sulfide reacted with a sulfide of phosphorus such as Pass. Thus an improved lubricating oil composition may consist of a, mineral lubricating oil containing between 0.5 and 5% of a mixture of calcium sulfonate and the reaction product of a barium tertiary octyl phenol sulfide with P285 and from 0.1 to 1% of mixed amyl alcohols. As a further specific example, the oil may. contain about 2% of a mixture of calcium sulfonate and the reaction product of barium tertiary octyl phenol sulfide with phosphorus pentasulfide and 0.5% of mixed amyl alcohols. If desired, however, the calcium salt of mineral oil-soluble sulfonic acids may be used alone as the detergent additive, in which case the oil composition might consist of a mineral lubricating oil containing between 0.5 and 5% of the calcium salt of mineral oil soluble sulfonic acids with 0.1 to 1% of mixed amyl alcohols as an oil soluble organic hydrophillc compound.

According to the present invention, oil soluble organic hydrophiiic compounds will, when present in compounded heavy duty oil and other lu bricants in amounts ranging from .05-'4% by weight and preferably 0.1-1% by weight, reduce to negligible proportions the additive separation caused by emulsification of the oil with water. The oil-soluble organic hydrophilic compounds may be blended into previously compounded oils by means of heat sufiicient to hasten solution. If desired the hydrophilic compounds can be incorporated in the oil concentrate of additives at the time that the concentrates are prepared, in which case the hydrophilic compounds will be incorporated in amounts ranging from i- 40% by weight based upon the weight of the detergent additives present in the oil concentrate, depending upon the concentration of oilsoluble hydrophilic compounds desired in the final compounded oil. Also if desired, the stabilizing agent may be incorporated in concentrates of other additives, such as anti-oxidant bearing corrosion inhibitors, film strength agents, thickeners, pour depressants and the like. However, it th stabilizing agent is incorporated in the concentrate for the purpose of stabilizing that concentrate against the action of water, then the former or lesser concentration of stabilizing agents should be used. The various detergent additives difier somewhat in their reactions toward water and the amount of detergent additive present is also infiuential in determining the amount of stabilizing agent required to effectively induce additive stabilization; however, the preferred range of 0.1-1% by weight of oil-soluble hydrophilic compound will, in most instances, be found sufficient to give adequate protection against emulsification and additive separation.

For the purpose of demonstrating the effectiveness of oil soluble organic hydrophilic compounds as emulsification preventives and as stabilizers against additive separation, 50 cc. of a rust preventive composition comprisin 18% lead oleate, 12% petroleum oil bright stock, and .5% sodium sulfonate in a solvent naphtha was violently agitated with 2% of water for a few minutes and a ray emulsion resulted. When 2% of mixed amyl alcohols was added to the rust preventive composition and the experiment repeated it was found that 6% of water could be agitated with the rust preventive composition without the formation of an emulsion.

In a test somewhat similar to the above, a highly refined S. A. E. 30 parafllnic lubricating oil was compounded with 1.5% of calcium sulfonate. cc. of this compounded oil was violently agitated with 1% by volume of water for several minutes. After standing overnight, 25% of the volume of the oil was precipitated as large curds. The supernatant oil by analysis showed a loss of 48% of the original concentration of the detergent additive. When this test was repeated with various stabilizing agents blended in the sulfonate-oil composition, the following results were obtained:

Table Per Cent Sediment Blend b Y Volume E. paraffinic lubricating oil 1.5% calcium a tate 5% lsocctyl phenol 5 a trimethyl cyciohexanol 5% tertiary amyl phenoxy ethanol 5% 2-ethyihexyl alcohol 5% diamyl oxylate monomethyl ether of ethylene glycol ace ) .1% phenoxy ethanol +.l% phenoxy isopropanol i1-.5% mono Z-ethylbutyl ether of ethylene g yco 1 Hazy solution.

The above data clearly show that the agents of this invention, the oil-soluble organic hydrophilic compounds, are very effective in counteracting additive separation resulting from water contamination of compounded lubricants.

It is to be understood that the crankcase oil, extreme pressure lubricant, rust preventive, etc., compositions of the invention may, and frequently will, contain other constituents than those mentioned above. For instance, the use of viscosity-index improvers, pour point depressants, oiliness agents, extreme pressure agents, bearing corrosion inhibitors, dyes, emulsifiers, organic bases, fatty materials, esters, polymers, sulfur containing compounds, halogen bearing substances, phosphorus oxide and sulfide reacted materials, sulfur chloride treated compounds, and the like is contemplated.

What is claimed is:

1. An improved lubricating oil composition consisting essentially of a mineral lubricating oil containing from 0.5 to 5.0% by weight based on the total composition of an alkaline earth metallo-organic detergent composition having a tendency to form emulsions and drop out of oil solution in the presence of water, and 0.05 to 4% of an oil soluble hydrophilic agent selected from the group which consists of phenoxy ethanol and phenoxy isopropanol for stabilizing said detergent in solution in said oil.

2. An improved lubricating oil composition ccnsisting essentially of a mineral lubricating oil containing from 0.5 to 5.0% by weight based on the total composition of an alkaline earth metallo-organic detergent composition having a tendency to form emulsions and dropout of oil solution in the presence of water, and 0.1 to 1% of an oil soluble hydrophilic agent selected from the group which consists of phenoXy ethanol and phenoxy isopropanol for stabilizing said detergent in solution in said 011.

3. A composition according to claim 1 wherein said hydrophilic agent is phenoxy ethanol.

JOHN C. ZIMMER. GORDON W. DUNCAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,122,593 Stafford July 5, 1938 2,270,577 Bergstrom Jan, 20, 1942 2,335,017 McNab Nov. 23, 1943 2,346,808 Winning Apr. 18, 1944 2,354,547 Richardson July 25, 1944 2,359,738 Schiermeir Oct. 10, 1944 2,366,817 Towne Jan. 9, 1945 2,370,080 Schreiber Feb. 20, 1945 2,371,763 Lazar Mar. 20, 1945 2,391,099 McNab Dec. 18, 1945 2,409,686 McNab Oct, 22, 1946 2,409,726 Winning Oct. 22, 1946 

